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The Mountain-Prairie Region


U.S. Fish and Wildlife Service
134 Union Boulevard
Lakewood, Colorado 80228

September 21, 2001

Ken Burton 202-208-5634
Sharon Rose 303-236-7917 x415


An extensive national database outlining the distribution of disease-associated pathogens in America's wild and free-ranging fish populations -- viewed as critical to fishery management decisions throughout the United States was unveiled today by the U.S. Fish and Wildlife Service. Scientists said it points to "a relatively healthy picture."

The National Wild Fish Health Survey is the first effort to develop a readily accessible, reliable and scientifically-sound database that documents the national distribution of specific pathogens (organisms capable of causing disease) in free-ranging fish. The project was prompted in 1996, in part, when whirling disease began killing trout in Montana and Colorado. Whirling disease has also been found in trout populations in 20 other states.

Biologists have expressed concern about earlier theories that more fish pathogens might be infecting fish populations previously believed immune to certain diseases, but the Survey does not show that to be happening.

Cathleen Short, Assistant Director for Fisheries and Habitat Conservation, said Senator Conrad Burns deserved credit for being "a driving force" behind making the Survey a reality. "Without the Senator's leadership, the Survey would not have happened. It is a critically important piece of work for which the entire nation can be grateful.

"Healthy fish mean a healthy environment and a healthy economy," said Short. "This Survey tells us about potential threats to the well-being of America's fish populations and helps managers see that this resource remains vital and abundant."

Short said that much of the present understanding of fish pathogens and the diseases they cause has been gained by observing captive fish populations in either hatcheries or laboratories, and that "surprisingly little is known about the prevalence of pathogens among wild, free-rangingfish. That's another reason why this Survey is very important."

Short said the Survey indicates that the overwhelming majority of fish tested from the wild are healthy, "and that's terrific news for the nation."

The Survey is conducted through a partnership of natural resource management organizations, including other Federal, Native American, State and private agencies and groups. It becomes available to fisheries managers and the public today on a Worldwide Web-based internet site, at

The Survey divides fish pathogens into two main groups: Principal Fish Pathogens andPathogens of Regional Importance. Principal Fish Pathogens are those tested at all nine U.S.Fish and Wildlife Service Fish Health Centers across the country. Many of those tested for the Survey are also included within the Service's National Fish Hatchery inspection program. Thisgroup is extensive and includes the organisms that cause whirling disease and bacterial kidneydisease. The other group of pathogens tested are those that the Fish Health Centers deemimportant in their part of the country. Those are called Pathogens of Regional Importance andinclude largemouth bass virus in the Southeast and Asian tapeworm in the Southwest.

Fish pathogens comprise a large and diverse group of organisms ranging from microscopic bacteria and viruses to large parasitic worms. The severity of disease caused by fish pathogensalso varies widely and depends on a number of important factors. Some pathogens cause only mild effects, if any, on individual fish while others may cause catastrophic die-offs of whole populations. Disease results from the unstable interaction of three main variables: the fish host, the fish pathogen and the water the fish live in. Fish are continually exposed to pathogens but generally become diseased when stressed by contaminants, poor water quality or other similar factors. A few pathogens may cause disease in healthy fish regardless of stress.

Understanding the distribution of fish pathogens throughout the United States will help strengthen the biological basis of laws and regulations that govern the sale and transport of aquatic species as well as aquaculture products. That information can help protect such industries from costly diseases and indirectly safeguard thousands of American jobs.

The Survey also promotes recreational fishing, ensuring that both wild fish and stocks enhanced with hatchery-reared fish are healthy and sustainable. Healthy recreational fisheries provide the base for 1.3 million jobs and $70 billion in economic output generated by more than 50 million anglers in the United States.

The Survey will also be an important aid to biologists working on restoration and recovery of threatened and endangered species. Knowledge about pathogens of imperiled species and the ecosystems into which they are to be reintroduced will significantly improve the success of such management actions in returning or restoring imperiled species to their natural habitats.

The U.S. Fish and Wildlife Service is the principal Federal agency responsible for conserving, protecting and enhancing fish, wildlife and plants and their habitats for the continuing benefit of the American people. The Service manages the 93-million-acre National Wildlife Refuge

System, which encompasses more than 530 national wildlife refuges, thousands of small wetlands and other special management areas. It also operates 70 national fish hatcheries, 64 fishery resource offices and 78 ecological services field stations. The agency enforces Federal wildlife laws, administers the Endangered Species Act, manages migratory bird populations, restores nationally significant fisheries, conserves and restores wildlife habitat such as wetlands, and helps foreign governments with their conservation efforts. It also oversees the Federal Aid program that distributes hundreds of millions of dollars in excise taxes on fishing and hunting equipment to state wildlife agencies.

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